20. Once inside the engine, the air that has been compressed and burned would then require a nozzle exit area even larger than the original freestream capture area in order to make good on the available thrust, but a conventional nozzle of this geometry would be too cumbersome to carry along. Instead, the entire afterbody underneath the vehicle is used as a free expansion surface, Flight erbody Waves Airbreathing Engine Fig. 20 Schematic diagrams of aerospace plane flowtield and configuration. 26 H Y P E R S O N IAIRBREATHING C PROPULSION as depicted in Fig.

The reference configuration is called the S£nger Space Transportation System, in honor of the famous rocket and hypersonic flight pioneer Eugen S~nger, who first designed vehicles intended to fly to and from space. Hs'la6 As shown in Fig. 15, it is a reusable, two-stage, blended wing/body vehicle that employs horizontal takeoff and landing on conventional runways. The S£nger system emphasizes cost, safety, reliability, and flexibility, and uses advanced state-of-the-art technologies. The piloted first or lower stage has also been known as the European Hypersonic Transport Vehicle (EHTV) because it has wide commonality with a potential hypersonic passenger aircraft.